| 摘要 |
PURPOSE:To obtain a titled prehardened molding material that provides a long life by contg. specific amts. of C, Si, Mn, Ni, Cr, (1/2W+Mo), and V in steel and refining these to a specific HB value range. CONSTITUTION:A prehardened molding material for casting of metals having high melting point is prepd. to the compsn. consisting, by weight %, of 0.08-0.2 (more particularly 0.1-0.15) C, <0.6 (more particularly <0.35) Si, 0.1-1.2 (more particularly 0.4-0.9) Mn, 0.1-1.2 (more particularly 0.4-1) Ni, 0.5-2 (more particularly 0.6-1.2) Cr, 0.1-1.1 (more particularly 0.2-0.7) (1/2W+Mo), 0.05-0.45 (more particularly 0.1-0.35) V, and the balance Fe and impurities. Further, this is refined to 170-331 HB. The material formulated to have the compsn. of low C-low Si-low-middle Ni-Mn-Mo(W)-V in this way hardens uniformly both in and out of large sized molds and will not crack. |
